Abstract

Effect of Hydrophilic Polymers on the Complexation and Solubilizing Efficiencies of Cyclodextrins

Author(s): K. P. R. Chowdary and A. Seetha Devi

The objective of the present investigation is to study the complexation of etoricoxib with two CDs, β -cyclodextrin and hydroxypropyl β -cyclodextrin for enhancing its solubility. The effect of three hydrophilic polymers namely PVP, HPMC and PEG on the complexation and solubilizing efficiencies of cyclodextrins was also investigated . The aqueous solubility of etor icoxib was linearly increased as a function of the concentration of β CD and HP β CD alone and in the presence of hydrophilic polymers, PVP, HPMC and PEG. The increase in solubility is due to the formation of a 1 : 1 M complex in solution in each case. The complexes formed between etoricoxib– CD were quite stable. Addition of hydrophilic polymers has markedly enhanced the complexation efficiency of CDs. PVP has given higher enhancement in the complexation efficiency of both; β CD and HP β CD. The order of hydrophilic polymers in enhancing the complexation efficiency was PVP > HPMC > PEG with both; β CD and HP β CD. Addition of hydrophilic polymers has markedly enhanced the solubilizing efficiency of both; β CD and HP β CD. HP β CD exhibited higher solubilizing efficien cy, when compared to β CD, both; alone and in th e presence of hydrophilic polymers. PVP has given highest enhancement (11.67-16.75 fold) in the solubilizing efficiency of CDs. Hence, a combination of CDs and hydrophilic polymers is recommended for enhancing the complexation and solubilizing efficiencies of CDs and to enhance the solubility of etoricoxib, a BCS class II drug.